Category Archives: Workflow

Issuing commands in order

Commands are processed in the order they appear in the intend_list. However, there are 2 types of commands: state, and action. State commands change the sprite variables, and Action commands both change sprite variables as necessary, and also change animation (that is, generate a new lookup).

Directional commands (d:#) are the only State commands. They change the seq_dir variable but they do not issue a PlayerSetAnimation implicitly. It allows for other situations to do that.

NPC animation sheets

NPC animation sheets were created alongside Player animation sheets and they are essentially copies with the main exception that all animation functions as described in the original document have an additional argument passed on to them, which is the UID of the sprite being changed.

In animating Player, this was easy because all references to Player was the same. With NPCs, it’s made so that it can accommodate changing animation across multiple sprites.

NPC animation maps

In the same way, NPC animation maps have been created on a per-NPC basis. Each NPC will have its own animation map named according to the name of the NPC.

NPCs in Tiled

Tied with the animation sheet system, the Facing parameter in Tiled, like the one for the Player, orients the NPC at load time (ie modifies the direction).

Details of how NPCs and other entities in Tiled are defined will be covered in later topic.

The Slidewalk system, taken from 2400AD is implemented by using several components in Tiled, and hooking them up in C2.

Tiled/TMX Component

The Slidewalk is comprised of several objects which are the children of an ObjectGroup; the ObjectGroup, in effect, is a single Slidewalk entity.

Components of a Slidewalk

What identifies an existence of Slidewalk is not the ObjectGroup, but the individual Objects which must be named starting with the prefix sw. Each Object component of the Slidewalk contains the name of the Slidewalk it belongs to. The name of the Slidewalk is the name of the ObjectGroup.

A Slidewalk must always have a path. A path is a Tiled polyline. It must be named swpath. The path will later define the waypoints of the Slidewalk. The swpathObject must also contain an attribute called speed. This is the speed value of this Slidewalk.

A Slidewalk must have at least one entry-only point. This point is defined by using an Object (parented under the Slidewalk in question). It must be named swin.

A Slidewalk must have at least one end-only point. This point must be named swend.

A Slidewalk may optionally have an exit point. This exit point may also be a potential entry point. Every point, whether it is an entry, exit, or end point, must begin with sw. Then use the keyword in to indicate this is an entry point, and the keyword out to indicate it is an exit point; these keywords may be used in the same point, such as swinout.

The exit and the end points must also contain a custom property called exitdir. This is a GridMove direction that specifies which direction the player will move towards when deciding the exit, in order to get off the movement effect of the Slidewalk.

C2 Implementation

In C2 the first step is to get the swpathObject to mark the waypoints of the MTiles. In the same procedure, they are marked with the name of the Slidewalk they belong to. The waypoint sequence index is internally based on how Tiled writes it, which is sequential anyway, so the C2 loop iterator does this conveniently.

As the MTiles are being tagged as waypoints, they are being added into the InstGroup with a group named after the Slidewalk’s name, which uniquely identifies these series of MTiles for SLG and GridMove. They are added in the order they are looped, so the sequence is still preserved at this point.

MTiles are then further marked with their entry/exit/end values, as well as the custom properties as inputted in Tiled.

When the player moves on top of the Slidewalk, the On GridMove reach target trigger will check whether the player is on an entry point. If it is, a function called CreatePathFromIG is called whereby it takes the Slidewalk InstGroup waypoints and transfers those waypoints to the player’s own InstGroup moving path. CreatePathFromIG does something more, though: it considers the possibility of multiple entry points; it finds the MTile that the player has entered from, and starts retrieving MTile waypoints from that point until the end.

Though this syntax was developed many months ago, I had forgotten to document this.

Overview

This edge definition refers to the edges that exists in any GTile tile/sprite. This obviously means that edge definition is a Tiled property of the GTile, which is then passed on in C2 to generate MTile edges at runtime.

Note that a GTile refers to a graphics tile which is a bigger-sized tile. An MTile refers to a movement tile which is smaller and forms the grid of possible tiles to move to. Every GTile is subdivided into equal square MTiles.

Edge definition

Below is an image representing one GTile, and the MTile IDs within it:

For every GTile, there can exist any number of edges. Using this image as an example:

That sprite is mapped out as:

Here, we introduce the edge syntax used to define those edges.

<mtile_id>:<gridmove_direction>[,<mtile_id>:<gridmove_direction>...]

Where mtile_id is the id of the MTile that needs an edge definition (because it is neighbouring a GTile edge), and gridmove_direction is the direction where the edge lies on that MTile specified in the GridMove format.

In the sprite above, the edge definition is:

1:0,5:0,8:3,9:3,10:3,11:3

That is, the MTile ID 1 and 5 have a edges at Direction 0 (east), IDs 8, 9, 10, and 11 have edge at Direction 3 (north). Note that it’s possible to have defined other MTiles, such as:

6:1,7:1

…to replace 10:3, 11:3. It doesn’t matter, as long as the same edge is not specified twice.

Tiled

Note that the edge definition is inputted in Tiled in its tilesheet editor. Currently, there are two Tile properties associated with edge: edge and edge4. edge was the original use, which subdivided each GTile into 2×2 MTiles. edge4 subdivided it further (4×4) giving it a maximum of 16 MTiles per GTile (this depicted in the image above).

In the C2 project, only one type is used and can be interchanged or modified depending on final design choices.

Some animations are not meant to be played in their totality before allowing the player to change states. For example, when the player is drawing the weapon out, the player is not allowed to move or draw the weapon back in before the weapon has been fully drawn.

No Interrupt

To do this, a no_interrupt variable has been introduced in the animation map which allows a specific animation to have this behaviour; this is transferred to C2 during runtime, of course.

Thus, all player commands are issued through several kinds of ‘intend action’ functions. Currently, they are:

PlayerUserCommand – handles the SWAP actions; queries if an animation is ok to interrupt or not

PlayerUserCommandDirection – handles directional actions (ie ‘d:#’); it also sees if an animation can be interrupted, and sets an integer intend_dir variable for use with other things in the game.

With the ongoing development in Animation Sheets, I’ve also formed a command syntax to allow flexibility in how actions are sequentially executed, while also being aware of sequence animation.

The flow in C2 is a bit convoluted so I want to document this for future reference.

intend_list

This is the variable that contains a sequence of ‘intended actions’ An example intend_list looks like this:

a:wepi,a:idle,w:as,a:wepo

Where:

<action_prefix>:<action>,<action_prefix>:<action>,...

An action_prefix can be ‘a’, ‘p’, ‘w’, ‘s’. This corresponds with ‘action’, ‘pose’, ‘weapon’, and ‘speed’, respectively. I’ll refer to this as SWAP for simplicity.

Actions can be move, wepi, wepo, shoot, idle.

Pose can be up, dn.

Weapon can be u, as, am, al (this is not yet implemented as of writing)

Speed can be walk, run.

C2 logic flow

Like I said, the flow jumps around.

The first, we start with a given animation. An animation is defined by SWAP, and SWAP are actually something like states. The SWAP is referred to in order to make the right decision which animation is to be played.

So even at the beginning, the SWAP is initialised manually and then PlayerSetAnimation, which is the function that does much of the decision-making is run, and in constantly run.

How it works

At the beginning of PlayerSetAnimation, the first item ([0]) in intend_list is read and then popped. (Since it is a string, it is implicitly tokenised; when I say ‘popped’ I mean that the first token is popped, since it is not really an array, though it is treated as such.)

The popped data is called command. The command is queried if it is an Action. If is not an Action, then the state variables of the SWP is set. For example, if the command is s:run, then the intend_speed variable, which is the internal C2 state variable for controlling actual speed, is set to "run".

One important note is that the intend_list commands continue to be popped until an Action is encountered (so that SWP are processed as state variable changes only).

However, if it is an Action, then it starts querying the SWP variables, then forming an appropriate lookup to the animation map list.

If it is Speed or Pose change then after setting the state variables, it will determine a lookup but uses the nominal animation with changed Pose or Speed variables.

The complicated bit

The complication lay in the combination of the implicit ‘next animation’ of one animation. Some important things to remember:

An animation, whether it has a sequence or not, will default to looping itself.

In the animation map, a ‘next animation’ can be specified. This makes one animation inherently connected to another.

I’ll demonstrate different intend_list examples and how they are processed, and what goes on beyond the PlayerSetAnimation function.

Example 1

Given an intend_list:

a:wepi,w:am,a:wepo

This is used when switching from a small weapon to a medium weapon, and only applies when a small weapon is equipped.

PlayerSetAnimation

When a:wepi is popped, ‘wepi’ is the intend_anim, which is the keyword. SWP variables are queried (although in this case only the pose and weapon are relevant). Then the animation lookup is set, in this case ‘am upwo’ (medium weapon, standing weapon out).

Remember that the intend_list is popped, so it now looks like this.

w:am,a:wepo

Then the lookup is used to get the seq_start/seq_end, and other variables needed to play the animation. The next_anim and is_seq variables are also populated.

PlayerPlayAnimation

Then PlayerPlayAnimation is called. What this function does is simply play the animation, and starts the playhead at the appropriate place. It doesn’t check anything; it just makes the animation run.

PlayerCheckAnimation

Then there is a On frame change C2 trigger, which calls the PlayerCheckAnimation function. This function checks to see if the sequence as ended. If the sequence’s parameters have been satisfied, it calls PlayerAdvanceSequence.

PlayerAdvanceSequence

PlayerAdvanceSequence is reponsible for determining what to do next. If there is a sequence of animation to be played (ie segmentations of the animation to be played discretely), then this function increments the sequence index. This is important, because as long as there is a sequence to be played, the system will continue to play the sequence.

If however, the sequence has been played out PlayerAdvanceSequence decides several things. First, does the current animation have a ‘next_anim’ name? In this example, the ‘wepi’ animation has ‘idle’ for its ‘next_anim’.

So if there is a ‘next_anim’ name, the next thing is to determine if there are any other Actions in the recently popped intend_list. In our case, yes. Remember our intend_list:

w:am,a:wepo

‘a:wepo’ is still present. So here, nothing special happens. The above intend_list is retained, and PlayerSetAnimation is called again.

Back to PlayerSetAnimation

When it is called again it sees ‘w:am’, and pops that. But we already know that PlayerSetAnimation will always keep on popping non-Action commands (setting variables as commanded by SWP). So after popping ‘w:am’, it sees the final command ‘a:wepo’ and pops that.

When the last is popped, intend_list is blank. But the whole process is repeated: the lookup is made, and then run. At some point, we end up in PlayerAdvanceSequence again, and then from here we ask the same questions. Does it have a ‘next_anim’ variable? Yes: ‘idle’.

Does it have any other Action in intend_list? No, it’s blank. When that happens, the default ‘next_anim’ is prepended to the intend_list (although because it’s blank, it doesn’t matter). Then the intend_list looks like:

a:idle

Then PlayerSetAnimation is called with that intend_list, in which is goes back to idle.

Example 2

Let’s try another intend_list going through the same process:

a:wepi,w:u

PlayerSetAnimation

‘a:wepi’ is processed and popped first in PlayerSetAnimation. Because it’s an Action, a lookup is immediately processed for it. Then the intend_list looks like:

w:u

After the lookup is processed, it is played and then checked like Example 1.

PlayerAdvanceSequence

Eventually we arrive at PlayerAdvanceSequence again when the ‘weapon in’ animation sequence is finished. The ‘weapon in’ animation has ‘idle’ for its ‘next_anim’.

PlayerAdvanceSequence queries if there are still any Action commands in the intend_list. There are none (ie ‘w:u’). So what happens is that the ‘next_anim’ is appended to the intend_list so that the PlayerSetAnimation knows it is the right time to use the ‘next_anim’. The intend_list now looks like this:

w:u,a:idle

So when PlayerSetAnimation is called with that intend_list, it processes and pops ‘w:u’, which switches the weapon to ‘unarmed’, and then processes/pops the Action ‘idle’. This completes the command sequence for this example.

Example 3

Given the this intend_list:

p:dn,s:run

These are just Pose and Speed changes, so they are considered separately.

PlayerSetAnimation

Pose and Speed commands change the intend_pose, and intend_speed variables. But a lookup must also be made for them in the same way Actions are. But the main difference is that in Pose and Speed, they are popped and processed immediately at the beginning with the setting of the variables. In our example, before a lookup is created, the intend_list would be empty, though the variables have been set (ie intend_pose=”dn”, intend_speed=”run”)

The lookup is made in the same place where Actions are. The main difference is that Speed and Pose uses the state variables to create the lookup. And just as importantly, it relies on the current PLAYER.anim variable to know what the current animation is.

PLAYER.anim

PLAYER.anim is an instance variable in the sprite which contains the ‘base’ animation which specifies only the Pose and the Action. Some examples:

If player is idle, unarmed, is standing, PLAYER.anim=”up idle”.

If player is idle, unarmed, is crouched, PLAYER.anim=”dn idle”.

If player is idle, small weapon drawn, crouched, PLAYER.anim=”dn idle”

If player is intending to run, crouching, unarmed, PLAYER.anim=”dn move w”

Note that PLAYER.anim doesn’t express whether a weapon is drawn or not.

Using PLAYER.anim, we can get the nominal state of movement. Then is a Pose change is required, then the Pose aspect of the PLAYER.anim is modified and PlayerPlayAnimation is called.

The rest goes through the same process again.

PLAYER.do_not_check

A variable called do_not_check is used for bypassing actual checking of frames during OnFrameChange. The reason behind this is because there is not much frame control when I switch animation folders. C2 only allows two options: start at the beginning of the animation folder, or the current frame. But because I’m using it as a map rather than as sequence, I’m jumping from one folder to another, so the frame numbers become arbitrary, based on the animation map. So either frame method is useless in this case. What was actually happening was that the frame being queried as the wrong value; when the the animation folder was switched to, and the play_start and play_end variables were populated (through the values in the map), the OnFrameChange event was triggered. The current AnimationFrame, at this point, is likely to be wrong, since I can only begin at the start, or at the current frame integer (which won’t correspond to a new animation folder). Therefore, I needed a way to prevent the check before I could properly set the frame at the next tick.

To do this, before calling an animation folder, I first put do_not_check=1, then call the animation folder (ie ‘Set animation (start at the beginning’). This has the instant effect of triggering OnFrameChange. But a condition checking the do_not_check variable will bypass it.

Conclusion

The main ideas are

intend_list is the the entry point for all animation changes

intend_list is popped and data is put into PLAYER.intend_anim

intend_anim is used to process what command this is

If a command is an Action, is processed normally

An animation lookup is constructed from the command itself

In addition, the other SWP variables are used

When a sequence has played out a check is made if there are still an Action command in the intend_list, to know whether the ‘next_anim’ animation needs to be played out.

If there are still Action commands, then the intend_list is fed back in PlayerSetAnimation.

If there are no other Action commands, the current animation’s ‘next_anim’ name is appended to intend_list and then is fed back to PlayerSetAnimation.

If a Pose or Speed change is made, the intend_pose and intend_speed variables are changed. Then the command is made a lookup using the nominal animation that is currently playing. The nominal animation is found out by referencing the PLAYER.anim variable.

Intentions

Animation being in sheets, can then be driven by separate variables that describe a few properties of an animation. These properties (also called intentions) are:

Action

idle

move

wepout

wepin

shoot

Pose

up

down

Speed

walk

run

Wep

unarmed

armed small

armed medium

armed large

Each of these properties are termed ‘intention’, which means that player intends, for example, to have a ‘walk’ speed, an ‘up’ pose, and ‘unarmed’. So when the ‘move’ action is called, it will find the appropriate animation to match ‘walk, up, unarmed’. If a ‘wepout’ action is called, that would not yield an animation, because the ‘intended’ weapon is ‘unarmed’. If the ‘wep’ was changed to ‘armed small’, then the animation will yield the player in standing pose, drawing a small weapon. The speed intention is not relevant here, of course; it’s only relevant when a specific action is needed to query that intention.

Multiple intentions

Multiple intentions are assumed in the system. This enables a number of actions and intentions to be strung up together to make a sequence of movements one after the other. Multiple intention are basically stringing up a series of intentions by commas; eg a:idle, a:move,p:dn,s:walk,w:u. Note the ‘a’, ‘p’, ‘s’, and ‘w’ prefixes which denote ‘action’, ‘pose’, ‘speed’, and ‘wep’, respectively. This specifically switches those intentions .

Note that even in animation maps, there is a key called ‘next_anim‘ which automatically moves from one animation to another. However, multiple intentions are prioritised first, so that if the intentions are written like a:wepin,a:wepout, then animation plays ‘wepin’ first, then ‘wepout’, but it will ignore the ‘next_anim‘ value of ‘wepin’. Since ‘wepout’ is the last intention, it will move to the animation of ‘wepout’s’ ‘next_anim‘, if any.